Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

A time storage unit (102) stores, for each of products included in a
predetermined product group, an assumed time that is assumed to be
required from start of usage of a product until end of usage of the
product. A history storage unit (101) stores history information
including a user identifier of a user who purchased any of the products
included in the product group, the purchased product, a purchase date and
time. An estimation unit (103) acquires history information associated
with a user identifier of a recommendation-receiving user, and estimates,
from the history information, a usage-end date and time of a most
recently purchased product based on a usage time required from start of
usage by the recommendation-receiving user of a product other than the
most recently purchased product until end of usage thereof and an assumed
time. A presentation unit (104) selects, from the product group, a
product other than the most recently purchased product, and presents a
message recommending the other selected products at the estimated date
and time.

Claims:

1. A product recommendation device comprising: a time storage unit to
store, for each of products included in a predetermined product group, an
assumed time that is assumed to be required from start of a product usage
until end of the product usage; a history storage unit to store history
information, the history information including a user identifier of each
user who purchased any of the products in the product group, the
purchased product, and a purchase date and time of the product; an
estimation unit that acquires, from the history information stored in the
history storage unit, history information associated with the user
identifier of a recommendation-receiving user, wherein the
recommendation-receiving user is a user who receives recommendation of a
product, determines, from the acquired history information, a usage time
required from start of usage by the recommendation-receiving user of a
product other than a product most recently purchased by the
recommendation-receiving user until end of usage of the product, and
estimates a date and time when the recommendation-receiving user finishes
using the most recently purchased product, based on the determined usage
time and the assumed time for the product associated with the acquired
history information, the assumed time being stored in the time storage
unit; and a presentation unit that selects, from the product group, a
product other than the product most recently purchased by the
recommendation-receiving user, and presents a message recommending the
other selected product to the recommendation-receiving user at the
estimated date and time.

2. The product recommendation device according to claim 1, wherein the
estimation unit sorts products associated with history of the
recommendation-receiving user stored in the history storage unit in order
of purchase date and time, such as product 1, product 2, . . . , product
n, determines a ratio c[i]=(T[i+1]-T[i])/A[i], for each of an integer
i=1, 2, . . . , n-1, from the purchase date and time represented by T[i]
when the recommendation-receiving user purchased the product i, the
purchase date and time represented by T[i+1] when the
recommendation-receiving user purchased the product (i+1), and the
assumed time represented by A[i] on the product i stored in the time
storage unit, estimates, from an array of the determined ratios c[1],
c[2], . . . , c[n-1], a ratio c[n] of the product n most recently
purchased by the recommendation-receiving user, and estimates the date
and time when the recommendation-receiving user finishes using the most
recently purchased product n to be T[n]+A[n]c[n], from the most recent
purchase date and time T[n], the estimated ratio c[n] and the stored time
A[n].

3. The product recommendation device according to claim 2, wherein the
estimation unit estimates the ratio c[n] of the product n most recently
purchased by the recommendation-receiving user by using a weighted mean
such that the ratio c[i] (i=1 to n-1) determined from the older purchase
history less contributes to the ratio c[n].

4. The product recommendation device according to claim 3, wherein the
estimation unit estimates a value obtained by multiplying the weighted
mean by a seasonal coefficient preliminarily defined according to a
season of the purchase date and time T[n] to be the ratio c[n].

5. The product recommendation device according to claim 2, wherein the
history information further includes a sales date and time when the
purchased product was sold, in the case where the
recommendation-receiving user sold the purchased product i, the
estimation unit compares the sales date and time represented by S[i] when
the product i was sold and the purchase date and time T[i+1] when the
product (i+1) was purchased, and if the sales date and time S[i] is
earlier than the purchase date and time T[i+1], the estimation unit
determines the ratio c[i] to be c[i]=(S[i]-T[i])/A[i]

6. The product recommendation device according to claim 2, wherein, the
history information further includes a sales date and time when the
purchased product was sold, in the case where the
recommendation-receiving user sold the purchased product i, the
estimation unit determines the ratio c[i] to be c[i]=(S[i]-T[i])/A[i]
using the sales date and time represented by S[i] of the product i.

7. The product recommendation device according to claim 5, wherein from
history information including both of the purchase date and time and the
sales date and time among the history information, an interval between
the purchase date and time and the sales date and time of the product
associated with the history information is determined, and the assumed
time stored in the time storage unit is adjusted of the product based on
the determined interval.

8. The product recommendation device according to claim 1, wherein the
assumed time stored in the time storage unit of a first product is
adjusted based on an interval between the purchase date and time included
in history information associated with the first product and the purchase
date and time included in history information associated with the second
product, the second product being the most recently purchased among
products purchased by the same user as that of the first product after
purchase of the first product, among the history information.

9. A product recommendation method performed by a product recommendation
device, the product recommendation device comprising: a time storage unit
to store, for each of products included in a predetermined product group,
an assumed time that is assumed to be required from start of a product
usage until end of the product usage; a history storage unit to store
history information, the history information including a user identifier
of each user who purchased any of the products in the product group, the
purchased product, and a purchase date and time of the product; an
estimation unit; and a presentation unit, the product recommendation
method comprising: an estimation step in which the estimation unit
acquires, from the history information stored in the history storage
unit, history information associated with the user identifier of a
recommendation-receiving user, wherein the recommendation-receiving user
is a user who receives recommendation of a product, determines, from the
acquired history information, a usage time required from start of usage
by the recommendation-receiving user of a product other than a product
most recently purchased by the recommendation-receiving user until end of
usage of the product, and estimates a date and time when the
recommendation-receiving user finishes using the most recently purchased
product. based on the determined usage time and the assumed time for the
product associated with the acquired history information, the assumed
time being stored in the time storage unit; and a presentation step in
which the presentation unit selects, from the product group, a product
other than the product most recently purchased by the
recommendation-receiving user, and presents a message recommending the
other selected product to the recommendation-receiving user at the
estimated date and time.

10. (canceled)

11. A non-transitory computer-readable recording medium recording a
program, the program causing a computer to function as: a time storage
unit to store, for each of products included in a predetermined product
group, an assumed time that is assumed to be required from start of a
product usage until end of the product usage; a history storage unit to
store history information, the history information including a user
identifier of each user who purchased any of the products in the product
group, the purchased product, and a purchase date and time of the
product; an estimation unit that acquires, from the history information
stored in the history storage unit, history information associated with
the user identifier of a recommendation-receiving user, wherein the
recommendation-receiving user is a user who receives recommendation of a
product, determines, from the acquired history information, a usage time
required from start of usage by the recommendation-receiving user of a
product other than a product most recently purchased by the
recommendation-receiving user until end of usage of the product, and
estimates a date and time when the recommendation-receiving user finishes
using the most recently purchased product, based on the determined usage
time and the assumed time for the product associated with the acquired
history information, the assumed time being stored in the time storage
unit; and a presentation unit that selects, from the product group, a
product other than the product most recently purchased by the
recommendation-receiving user, and presents a message recommending the
other selected product to the recommendation-receiving user at the
estimated date and time.

12. The product recommendation device according to claim 6, wherein from
history information including both of the purchase date and time and the
sales date and time among the history information, an interval between
the purchase date and time and the sales date and time of the product
associated with the history information is determined, and the assumed
time stored in the time storage unit is adjusted of the product based on
the determined interval.

Description:

TECHNICAL FIELD

[0001] The present invention relates to a product recommendation device, a
product recommendation method, a program and a recording medium that
recommend a product to a user at a suitable timing.

BACKGROUND ART

[0002] A shopping system that allows for transaction of products,
services, and/or the like through, for example, web pages has been known.
In such a system, an art is known that introduces advertisements and
products suitable for a user in order to encourage the user to purchase a
product and/or the like. For example, Patent Literature 1 discloses an
art to select an advertisement for presentation to a user based on
information on the user's attribute and advertisements that the user has
previously clicked. When a product is introduced to a user, it is common
to predict a purchase timing when the user will purchase the product
based on a purchase history if the user has repeatedly purchased the
product.

PRIOR ART LITERATURE

Patent Literature

[0003] Patent Literature 1: Japanese Patent No. 3984473

DISCLOSURE OF INVENTION

Problem to be Solved by the Invention

[0004] However, for certain types of products such as games or books, the
same product is rarely purchased again, and the time when usage of a
purchased product finishes varies according to each product. For such a
product, it is difficult to predict the next purchase time from the
purchase history and recommend the product at a suitable moment.

[0005] The present invention solves the above problem, and is intended to
provide a product recommendation device, a product recommendation method,
a program and a recording medium that are suitable for estimating the
time when a user finishes using a product and recommending a product to
the user at a suitable timing, with respect to a type of products of
which time required to finish usage varies according to each purchased
product.

Means for Solving the Problems

[0006] A product recommendation device according to a first aspect of the
present invention includes:

[0007] a time storage unit to store, for each of products included in a
predetermined product group, an assumed time that is assumed to be
required from start of a product usage until end of the product usage;

[0008] a history storage unit to store history information, the history
information including a user identifier of each user who purchased any of
the products in the product group, the purchased product, and a purchase
date and time of the product;

[0009] an estimation unit that acquires, from the history information
stored in the history storage unit, history information associated with
the user identifier of a user who receives recommendation of a product
(hereinafter referred to as "recommendation-receiving user"), determines,
from the acquired history information, a usage time required from start
of usage by the recommendation-receiving user of a product other than a
product most recently purchased by the recommendation-receiving user
until end of usage of the product, and estimates a date and time when the
recommendation-receiving user finishes using the most recently purchased
product, based on the determined usage time and the assumed time for the
product associated with the acquired history information, the assumed
time being stored in the time storage unit; and

[0010] a presentation unit that selects, from the product group, a product
other than the product most recently purchased by the
recommendation-receiving user, and presents a message recommending the
other selected product to the recommendation-receiving user at the
estimated date and time.

[0011] In the product recommendation device according to the first aspect
of the present invention,

[0012] the estimation unit may

[0013] sort products associated with history of the
recommendation-receiving user stored in the history storage unit in order
of purchase date and time, such as product 1, product 2, . . . , product
n,

[0014] determine a ratio c[i]=(T[i+1]-T[i])/A[i], for each integer i=1, 2,
. . . n-1, from the purchase date and time represented by T[i] when the
recommendation-receiving user purchased the product i, the purchase date
and time represented by T[i+1] when the recommendation-receiving user
purchased the product (i+1), and the assumed time represented by A[i] on
the product i stored in the time storage unit,

[0015] estimate, from an array of the obtained ratios c[1], c[2], . . .
c[n-1], a ratio c[n] of the product n most recently purchased by the
recommendation-receiving user, and

[0016] estimate the date and time when the recommendation-receiving user
finishes using the most recently purchased product n to be T[n]+A[n]c[n],
from the most recent purchase date and time T[n], the estimated ratio
c[n] and the stored time A[n].

[0017] In the product recommendation device according to the first aspect
of the present invention,

[0018] the estimation unit may estimate the ratio c[n] of the product n
most recently purchased by the recommendation-receiving user by using a
weighted mean such that the ratio c[i] (i=1 to n=1) determined from the
older purchase history less contributes to the ratio c[n].

[0019] Alternatively, in the product recommendation device according to
the first aspect of the present invention,

[0020] the estimation unit may estimate a value obtained by multiplying
the weighted mean by a seasonal coefficient preliminarily defined
according to a season of the purchase date and time T[n] to be the ratio
c[n].

[0021] In the product recommendation device according to the first aspect
of the present invention,

[0022] the history information may further include a sales date and time
when the purchased product was sold, and

[0023] in the case where the recommendation-receiving user sold the
purchased product i, the estimation unit compares the sales date and time
represented by S[i] when the product i was sold and the purchase date and
time T[i+1] when the product (i+1) was purchased, and if the sales date
and time S[i] is earlier than the purchase date and time T[i+1], the
estimation unit may determine the ratio c[i] to be c[i]
=(S[i]-T[i])/A[i].

[0024] Alternatively, in the product recommendation device according to
the first aspect of the present invention,

[0025] the history information may further include a sales date and time
when the purchased product was sold, and

[0026] in the case where the recommendation-receiving user sold the
purchased product i, the estimation unit may determine the ratio c[i] to
be c[i] =(S[i]-T[i])/A[i], using the sales date and time represented by
S[i] of the product i.

[0027] Alternatively, in the product recommendation device according to
the first aspect of the present invention,

[0028] from history information including both of the purchase date and
time and the sales date and time among the history information, an
interval between the purchase date and time and the sales date and time
of the product associated with the history information may be determined,
and the assumed time stored in the time storage unit may be adjusted of
the product based on the determined interval.

[0029] Alternatively, in the product recommendation device according to
the first aspect of the present invention,

[0030] the assumed time stored in the time storage unit of a first product
may be adjusted based on an interval between the purchase date and time
included in history information associated with the first product and the
purchase date and time included in history information associated with
the second product, the second product being the most recently purchased
among products purchased by the same user as that of the first product
after purchase of the first product, among the history information.

[0031] A product recommendation method according to a second aspect of the
present invention,

[0032] the product recommendation method being performed by a product
recommendation device, the product recommendation device comprising: a
time storage unit to store, for each of products included in a
predetermined product group, an assumed time that is assumed to be
required from start of a product usage until end of the product usage; a
history storage unit to store history information, the history
information including a user identifier of each user who purchased any of
the products included in the product group, the purchased product, and a
purchase date and time of the product; an estimation unit; and a
presentation unit,

[0033] the product recommendation method comprises:

[0034] an estimation step in which the estimation unit acquires, from the
history information stored in the history storage unit, history
information associated with the user identifier of a user who receives
recommendation of a product (hereinafter referred to as
"recommendation-receiving user"), determines, from the acquired history
information, a usage time required from start of usage by the
recommendation-receiving user of a product other than a product most
recently purchased by the recommendation-receiving user until end of
usage of the product, and estimates a date and time when the
recommendation-receiving user finishes using the most recently purchased
product, based on the determined usage time and an assumed time for the
product associated with the acquired history information, the assumed
time being stored in the time storage unit; and

[0035] a presentation step in which the presentation unit selects, from
the product group, a product other than the product most recently
purchased by the recommendation-receiving user, and presents a message
recommending the other selected product to the recommendation-receiving
user at the estimated date and time.

[0036] A program according to a third aspect of the present invention
causes

[0037] a computer to function as:

[0038] a time storage unit to store, for each of products included in a
predetermined product group, an assumed time that is assumed to be
required from start of a product usage until end of the product of usage;

[0039] a history storage unit to store history information, the history
information including a user identifier of each user who purchased any of
the products in the product group, the purchased product, and a purchase
date and time of the product;

[0040] an estimation unit that acquires, from the history information
stored in the history storage unit, history information associated with
the user identifier of a user who receives recommendation of a product
(hereinafter referred to as "recommendation-receiving user"), determines,
from the acquired history information, a usage time required from start
of usage by the recommendation-receiving user of a product other than a
product most recently purchased by the recommendation-receiving user
until end of usage of the product, and estimates a date and time when the
recommendation-receiving user finishes using the most recently purchased
product, based on the determined usage time and the assumed time for the
product associated with the acquired history information, the assumed
time being stored in the time storage unit; and

[0041] a presentation unit selects, from the product group, a product
other than the product most recently purchased by the
recommendation-receiving user, and presents a message recommending the
other selected product to the recommendation-receiving user at the
estimated date and time.

[0042] A computer-readable recording medium according to a fourth aspect
of the present invention, the program causing

[0043] a computer to function as:

[0044] a time storage unit to store, for each of products included in a
predetermined product group, an assumed time that is assumed to be
required from start of a product usage until end of the product usage;

[0045] a history storage unit to store history information, the history
information including a user identifier of each user who purchased any of
the products in the product group, the purchased product and a purchase
date and time of the product;

[0046] an estimation unit that acquires, from the history information
stored in the history storage unit, history information associated with
the user identifier of a user who receives recommendation of a product
(hereinafter referred to as "recommendation-receiving user"), determines,
from the acquired history information, a usage time required from start
of usage by the recommendation-receiving user of a product other than a
product most recently purchased by the recommendation-receiving user
until end of usage the product, and estimates a date and time when the
recommendation-receiving user finishes using the most recently purchased
product, based on the determined usage time and the assumed time for the
product associated with the acquired history information, the assumed
time being stored in the time storage unit; and

[0047] a presentation unit selects, from the product group, a product
other than the product most recently purchased by the
recommendation-receiving user, and presents a message recommending the
other selected product to the recommendation-receiving user at the
estimated date and time.

[0048] The program according to the present invention can be recorded on a
computer-readable information recording medium such as a compact disk,
flexible disk, hard disk, magnetic optical disk, digital video disk,
magnetic tape, semiconductor memory and/or the like.

[0049] The program can be distributed and sold via a computer
communication network, independently from a computer on which the program
is executed. The information recording medium can be also distributed and
sold independently from a computer.

Effect of the Invention

[0050] The present invention can provide a product recommendation device,
a product recommendation method, a program and a recording medium that
are suitable for estimating a date and time when a user finishes using a
product and recommending a product to the user at a suitable timing, for
a type of products of which time required to finish using varies
according to each purchased product.

BRIEF DESCRIPTION OF DRAWINGS

[0051]FIG. 1 is a diagram illustrating a relationship between a product
recommendation device according to an embodiment of the present invention
and a terminal device operated by a user;

[0052]FIG. 2 is a diagram illustrating a schematic configuration of a
typical information processing device in which a product recommendation
device according to an embodiment of the present invention is realized;

[0053]FIG. 3 is a diagram illustrating a schematic configuration of the
product recommendation device;

[0055]FIG. 5 is a diagram for explaining a history table according to
Embodiment 1;

[0056]FIG. 6 is a diagram for explaining an average usage time table
according to Embodiment 1;

[0057] FIG. 7 is a diagram for explaining a recommendation-receiving user
history table according to Embodiment 1;

[0058]FIG. 8 is a diagram for explaining a product recommendation message
presented to the recommendation-receiving user;

[0059]FIG. 9 is a flow chart for explaining processing performed by each
unit of the product recommendation device according to Embodiment 1;

[0060]FIG. 10 is a flow chart for explaining a usage-end date and time
estimation processing performed by an estimation unit of the product
recommendation device according to Embodiment 1;

[0061]FIG. 11 is a diagram for explaining a seasonal coefficient table;

[0062]FIG. 12 is a flow chart for explaining a usage-end date and time
estimation processing performed by an estimation unit of a product
recommendation device according to Embodiment 2;

[0063]FIG. 13 is a diagram illustrating a purchase and sales activity by
a user;

[0064]FIG. 14 is a diagram for explaining a history table according to
Embodiment 3;

[0065]FIG. 15 is a diagram for explaining a recommendation-receiving user
history table according to Embodiment 3;

[0066]FIG. 16 is a flow chart for explaining processing performed by each
unit of a product recommendation device according to Embodiment 3;

[0067]FIG. 17 is a flow chart for explaining a usage-end date and time
estimation processing performed by an estimation unit of the product
recommendation device according to Embodiment 3; and

[0068]FIG. 18 is a flow chart for explaining a usage-end date and time
estimation processing performed by an estimation unit of a product
recommendation device according to Embodiment 4;

MODE(S) FOR CARRYING OUT THE INVENTION

[0069] A product recommendation device 100 according to an embodiment of
the present invention, as illustrated in FIG. 1, connects to the Internet
300, to which a plurality of terminal devices 201, 202 to 20n operated by
users are connected. The user uses the terminal device 201, 202 or 20n to
purchase or sell a product. The product recommendation device 100
receives information and/or the like on products purchased by users
through the Internet 300 from the terminal devices 201, 202 to 20n of a
plurality of users and recommends a predetermined product to the users of
the terminal devices 201, 202 to 20n at a suitable timing.

[0070] A typical information processing device 400 will be described in
which the product recommendation device 100 according to an embodiment of
the present invention is realized.

[0072] The CPU 401 that controls the entire operation of the information
processing device 400, is connected to each of the components, and sends
to and receives from each of the components control signals and data.

[0073] The ROM 402 stores an IPL (initial program loader) that is executed
immediately after power-on, and by executing the IPL, a predetermined
program is read out to the RAM 403, thereby starting execution by the CPU
401. The ROM 402 stores an operating system program and various data that
are necessary for controlling the entire operation of the information
processing device 400.

[0074] The RAM 403 temporarily stores data and programs and keeps a
program and data read out from a DVD-ROM and other data necessary for
communication.

[0075] The NIC 404 is used for connecting the information processing
device 400 to a computer communication network such as the Internet 300
and is composed of, for example, what is in compliance with a
10BASE-T/100BASE-T standard used for establishing a LAN (local area
network), an analog modem for connecting to the Internet through a phone
line, an ISDN (integrated services digital network) modem, an ADSL
(asymmetric digital subscriber line) modem, a cable modem for connecting
to the Internet through a cable television circuit and/or the like, as
well as an interface (not shown) intermediating between any of them and
the CPU 401.

[0076] The image processing unit 405 processes data read from a DVD-ROM
and/or the like by an image arithmetic processor (not shown) in the CPU
401 or the image processing unit 405, and then records the processed data
on a frame memory (not shown) in the image processing unit 405. The image
information recorded on the frame memory is converted to video signals at
a predetermined synchronizing time and then output to the monitor 411,
thereby allowing for various image displays.

[0077] The speech processing unit 406 converts speech data readout from a
DVD-ROM and/or the like to analog speech signals, which then are output
from the speaker 412 connected to the speech processing unit 406. Under
control of the CPU 401, the speech processing unit 406 generates sounds
to be emitted during progress of processing by the information processing
device and causes the speaker 412 to output a speech corresponding to the
sounds.

[0078] A DVD-ROM loaded into the DVD-ROM drive 407 stores, for example, a
program for realizing the product recommendation device 100 according to
an embodiment. Under control of the CPU 401, the DVD-ROM drive 407
performs read-out processing on a DVD-ROM loaded thereto to read out a
necessary program and data, which are temporarily stored in the RAM 403
and/or the like.

[0081] The controller 410 receives operation inputs performed during
various setups of the information processing device 400. A user of the
information processing device 400 performs instruction inputs via the
controller 410 to record these data on the external memory 409, as
needed.

[0082] The monitor 411 displays data outputted from the image processing
unit 405 to the user of the information processing device 400.

[0083] The speaker 412 presents speech data output from the speech
processing unit 406 to the user of the information processing device 400.

[0084] In addition, the information processing device 400 may be
configured to perform the same function as that of the ROM 402, RAM 403,
external memory 409, DVD-ROM loaded into the DVD-ROM drive 407 and/or the
like using an external mass storage device such as a hard disk and/or the
like.

[0085] A functional configuration of a product recommendation device 100
according to Embodiments 1 to 3 realized in the information processing
device 400 will be described with reference to FIGS. 1 to 17. By turning
on the information processing device 400, a program is executed to cause
the information processing device 400 to function as the product
recommendation device 100 according to the Embodiments, thereby realizing
the product recommendation device 100 according to Embodiments 1 to 3.

EMBODIMENT 1

[0086] A product recommendation device 100 according to Embodiment 1 uses
information on an amount of time that is assumed to be used by an average
user of a product and information on an interval between purchases of
products, thereby to estimate a date and time when a user finishes using
a product and recommend a predetermined product on the estimated date and
time passed.

[0087] The product recommendation device 100 according to Embodiment 1, as
illustrated in FIG. 3, is composed of a history storage unit 101, a time
storage unit 102, an estimation unit 103 and a presentation unit 104.

[0088] A function of each unit will be described using as an example a
case where a user X performs a purchase activity as illustrated in FIG.
4.

[0089] The history storage unit 101 stores history information that
includes a user identifier of each user who purchased any of products
included in the predetermined product group, the purchased product, and a
purchase date and time of the product.

[0090] Accordingly, the RAM 403 or the external memory 409 functions as
the history storage unit 101.

[0091] In this specification, a product group means, for example, "Food",
"Game", "Book", "DVD" and/or the like, that is, a category of products of
which usage tendency of a user is the same; and the predetermined product
group is a category of products in which there is a low possibility of
repeatedly purchasing the same product. As for products included in the
predetermined product group, start of usage and end of usage can be
specified. That is, since a product such as "water" and "rice" included
in "Food" is repeatedly purchased, it does not belong to the
predetermined product group. Meanwhile, since, in the product group such
as "Game", "Book", or "DVD", there is a low possibility of repeatedly
purchasing the same product, the group is deemed to be the predetermined
product group. A product included in the product group of "Book" is, for
example, a product such as "a novel" and "a magazine" that has start of
usage (start of reading) and end of usage (end of reading). Meanwhile,
although a product such as "a dictionary" also belongs to the product
group of "Book", it is common that a dictionary is repeatedly and
continuously used, and therefore end of usage cannot be specified.
Accordingly, such a product is excluded from products in the product
group of "Book".

[0092] Specifically, the history storage unit 101 stores a table
(hereinafter referred to as "a history table 101a") in which a user ID
101a1 of a user who purchased a product, a product group 101a2 to which
the product purchased by the user belongs, the purchased product 101a3
(p[i] (i=1 to N, N: an arbitrary number)), and a purchase date and time
101a4 (t[i] (i=1 to N)) are associated with one another and registered. A
purchase history registered in the history table 101a relates to a
product that belongs to the predetermined product group; and a purchase
history of a product that belongs to a product group other than the
predetermined product group is not registered.

[0093]FIG. 5 illustrates an example of a history table 101a in the case
where a user X (a user ID thereof is "X") performs a purchase activity
illustrated in FIG. 4.

[0094] The user X purchased 15 products p[i] (i=1 to 15), eight of which
are products of the predetermined product group ("Game", "Book" and
"DVD"). Products registered in the history table 101a are products in a
group, such as "Game", "Book" or "DVD", that has a low possibility of
repeatedly purchasing the same product, and a product such as food that
is regularly and periodically purchased is not registered in the history
table 101a. Accordingly, a purchase history of "food 1" is not registered
in the history table 101a. If the user X purchases a product "a game 3"
in the predetermined product group at 22:00 on April 7, a user ID "X", a
product group "Game" to which the game 3 belongs, a product "game 3", and
a purchase date and time "22:00 on April 7" are associated with one
another and registered in the history table 101a.

[0095] Similarly, a purchase history for a product that belongs to the
predetermined product group is registered in the history table 101a. In
the history table 101a, a purchase history of a user other than the user
X is also registered, as with the user X.

[0096] The time storage unit 102 stores, for each of products included in
the predetermined product group, an assumed time that is assumed to be
required from start of usage of the product until end of usage thereof.

[0097] Accordingly, the RAM 403 or the external memory 409 functions as
the time storage unit 102.

[0098] The assumed time is, for example, an amount of time required from
start of usage by an average user of a product until end of usage thereof
(hereinafter referred to as "average usage time"). The average usage time
is, for example, an amount of time required by an average user to beat a
game that is provided by a manufacture of the game product or an amount
of time required by an average user to finish a book that is provided by
a publisher of the book. Alternatively, an average usage time may be for
example, an amount of time obtained by averaging periods from purchase of
a product until purchase of another product in the same product group by
other users on the product recommendation device 100, or an amount of
time obtained by averaging periods from purchase of a product until later
sale of the product by other users on the product recommendation device
100. Hereinafter, an assumed time stored in the time storage unit 102
will be described as the average usage time.

[0099] Specifically, the time storage unit 102 stores a table (hereinafter
referred to as "average usage time table 102a") to which a predetermined
product group 102a1, a product 102a2 included in the product group 102a1,
and an average usage time 102a3 of the product are associated with one
another and registered. An example of the average usage time table 102a
is illustrated in FIG. 6. In the average usage time table 102a, an
average usage time 102a3 is registered for each of x pieces of products
belonging to a product group "Game", that is, "game 1" to "game x", each
of y volumes of products belonging to a product group "Book", that is,
"book 1" to "book y", each of z pieces of products belonging to a product
group "DVD", that is, "DVD 1" to "DVD z" and so on. For example, an
average usage time "20" of a product "game 1" indicates that an average
user takes 20 hours to beat the product "game 1". In the case where a
product is a book, an average usage time indicates an amount of time
required by an average user to finish reading the book, and in the case
where a product is a DVD, an average usage time indicates an amount of
time required by an average user to finish watching the DVD.

[0100] The estimation unit 103 acquires, from the history information
stored in the history storage unit 101, history information associated
with a user identifier of each user who receives recommendation of a
product (hereinafter referred to as "recommendation-receiving user"),
determines, from the acquired history information, a usage time required
from start of usage by the recommendation-receiving user of a product
other than a product most recently purchased by the
recommendation-receiving user until end of usage thereof, and estimates a
date and time when the recommendation-receiving user finishes using the
most recently purchased product (hereinafter referred to as "usage-end
date and time") on the basis of the determined usage time and an assumed
time on the product associated with the acquired history information, the
assumed time being stored in the time storage unit 102.

[0101] Accordingly, the CPU 401 functions as the estimation unit 103.

[0102] Hereinafter, a method will be described in which the estimation
unit 103 estimates a usage-end date and time of a product P[n] (n: an
arbitrary number) most recently purchased by the recommendation-receiving
user.

[0103] First, the estimation unit 103 extracts, from history information
recorded in the history table 101a, history information on a product
group to which a product most recently purchased by the
recommendation-receiving user belongs, sorts the extracted history
information in order of purchase date and time, and temporarily stores
the sorted history information in the RAM 403. Hereinafter, the sorted
table will be referred to as "recommendation-receiving user history table
103a". In the recommendation-receiving user history table 103a, a user ID
103a1 of the recommendation-receiving user, a product group 103a2 to
which a product purchased by the user belongs, the purchased product
103a3 (P[i] (i=1 to n)), and a purchase date and time 103a4 (T[i] (i=1 to
n)) are associated with one another and registered. The estimation unit
103 also refers to the average usage time table 102a to determine an
average usage time A[i] (i=1 to n) of the purchased product P[i] (i=1 to
n). The determined average usage time A[i] (i=1 to n) is registered as an
average usage time 103a5 of the recommendation-receiving user history
table 103a.

[0104] FIG. 7 illustrates an example of a recommendation-receiving user
history table 103a.

[0105] For example, referring to a recommendation-receiving user as a user
X, and a usage-end date and time of a purchased product "game 2" will be
determined based on the history table 101a in FIG. 5. In this case, the
estimation unit 103 extracts, from the history table 101a in FIG. 5,
history information that is associated with the user X and a product
group "Game", and sorts the extracted history information in order of
purchase date and time, as illustrated in the recommendation-receiving
user history table 103a of FIG. 7. Next, referring to the average usage
time table 102a in FIG. 6, the estimation unit 103 determines an average
usage time A[1] (60 hours) of a purchased product P[1] (game 3), an
average usage time A[2] (20 hours) of a product P[2] (game 1), an average
usage time A[3] (30 hours) of a product P[3] (game 5), an average usage
time A[4] (40 hours) of a product P[4] (game 4) and an average usage time
A[5] (50 hours) of a product P[5] (game 2), all of the products belonging
to a product group "Game", and registers all of the average usage time in
the recommendation-receiving user history table 103a of FIG. 7.

[0106] Next, the estimation unit 103 determines an interval between
purchases T[i+1]-T[i] (i=1 to n-1) of products P[i] (i=1 to n-1) other
than a product P[n] most recently purchased by the
recommendation-receiving user. Generally, if after purchase of a product
P[i], a product P[i+1] that belongs to the same product group as that of
the product P[i] is purchased, it is deemed that usage of the product
P[i] has finished. For example, if, after purchase by the user X of a
product "game 3", the user X purchases "game 1" that belongs to the same
product group as that of "game 3", it is deemed that the user X has
beaten "game 3" or becomes bored with "game 3" and purchases the new
"game 1". Accordingly, in the present embodiment, a purchase date and
time T[i+1] is deemed as a date and time when usage of the product P[i]
has finished, and an interval between purchases T[i+1]-T[i] is deemed as
an amount of time required by the user to finish using the product P[i].

[0107] The estimation unit 103 determines a ratio c[i]=(T[i+1]-T[i])/A[i]
(hereinafter referred to as "usage time ratio") between an amount of time
T[i+1]-T[i] (i=1 to n-1) required by the user to finish using the product
P[i] (i=1 to n-1) (hereinafter referred to as "usage time") and an amount
of time A[i] (i=1 to n-1) required by an average user to finish using the
product P[i] (i=1 to n-1) (average usage time). A usage time ratio c[i]
(i=1 to n-1) indicates that the greater a usage time ratio c[i] becomes,
the more time the recommendation-receiving user takes to finish using the
product, compared with an average user. The average usage time A[i] (i=1
to n) of the product P[i] (i=1 to n) is often an amount of time required
to finish using the product P[i] (i=1 to n) when the product is
continually used, whereas a usage time T[i+1]=T[i] is an interval between
purchases. Therefore, a usage time ratio c[i] (i=1 to n-1) is generally
greater than one.

[0108] In the example of FIG. 7, the estimation unit 103 determines a
usage time T[2]=T[1] (=216 hours) of a product P[1], a usage time
T[3]-T[2] (=97 hours) of a product P[2], a usage time T[4]=T[3] (=144
hours) of a product P[3], and a usage time T[5]-T[4] (=70 hours) of a
product P[4]. Then, the estimation unit 103 determines a usage time ratio
c[1] (=3.60) of a product P[1], a usage time ratio c[2] (=4.85) of a
product P[2], a usage time ratio c[3] (=4.80) of a product P[3], and a
usage time ratio c[4] (=1.75) of a product P[4], based on the determined
usage time T[i+1]-T[i] (i=1 to n-1) and the average usage time A[i] (i=1
to n-1).

[0109] Next, the estimation unit 103 determines a usage time ratio c[n]
between a usage time (T[n+1]-T[n]) of the most-recently purchased product
P[n], and an average usage time A[n] of the product. Since a date and
time when usage of the product P[n] is finished, that is, a purchase date
and time T[n+1] of a new product P[n+1] is not a measured value, c[n] is
estimated based on the determined c[i] (i=1 to n-1). In the present
embodiment, assuming that the usage time ratio c[i] (i=1 to n-1)
determined from an older purchase history less contributes to c[n], c[n]
is determined as follows:

c[n]=Σi-1n-1c[i]'wn-i-1/Σi-1n-1w.su-
p.n-i-1 Expression 1

where w is a number greater or equal to zero and less or equal to one,
and can be arbitrarily set.

[0110] For example, in the example (n=5) of FIG. 7, assuming that w=0.95,
it follows that c[5]=3.71.

[0111] Then the determined c[n] is used to determine a usage-end date and
time T[n+1] of a product P[n] as follows:

T[n+1]=T[n]+A[n]c[n] Expression 2

[0112] For example, in the example in FIG. 7, since A[5]c[5]=185.5 hours,
a usage-end date and time T[6] of a product P[5] (game 2) is determined
as "14:30 on May 7".

[0113] The presentation unit 104 selects a product other than the product
most recently purchased by a recommendation-receiving user from a product
group of the most recently purchased product and presents a message
recommending the other selected products to the recommendation-receiving
user (hereinafter referred to as "product recommendation message") at the
date and time estimated by the estimation unit 103.

[0115] For example, when a usage-end date and time T[n+1] estimated by the
estimation unit 103 is reached, the presentation unit 104 displays on the
monitor 411 an image 500 (FIG. 8) showing information on a product that
belongs to the same product group as that of a product P[n] purchased by
the user and is suitable to be recommended to the user X. When the
estimated usage-end date and time is reached, the image 500 may be sent
to a preliminarily registered e-mail address of the user X.
Alternatively, after the estimated usage-end date and time is reached,
the user's login to a purchase site of a product and/or the like may
cause a browser to display the image 500.

[0116] A way to select a product to recommend is arbitrary. A product to
recommend may be randomly selected from products that belong to the
product group of the product P[n] and were not purchased in the past. By
judging the recommendation-receiving user's preference based on the
purchase history of the user, a product that has the highest possibility
to be purchased may be selected as a product to be recommended.
Alternatively, the most popular product may be selected as a product to
be recommended.

[0117] In the present embodiment, the predetermined product group is
described using contents such as "Game", "Book", "DVD" and/or the like as
an example, but the predetermined product group is not limited to these
contents. For example, the predetermined product group may be "home
appliances" such as a refrigerator, "automobiles" and/or the like of
which durable years are decided. In this case, the durable years can be
used as the average usage time.

[0118] Next, operation performed by each unit of the product
recommendation device 100 will be described with reference to flow charts
in FIGS. 9 and 10. When the product recommendation device 100 is turned
on, the CPU 401 starts product recommendation processing shown in the
flow chart in FIG. 9. Hereinafter, referring to the
recommendation-receiving user as a user X, a case where the user X
performs the purchase activity shown in FIGS. 4 and 5 will be described
as an example.

[0119] The CPU 401 determines whether a product in a predetermined product
group was purchased (Step S101). If the CPU 401 determines that the
product was purchased (Step S101; Yes), a user ID of a user who purchased
the product, a product group to which the purchased product belongs, the
purchased product p[N] and a purchase date and time t[N] are associated
with one another and registered in the history table 101a (Step S102).
Meanwhile, if the CPU 401 determines that the product in the
predetermined product group has not been purchased (Step S101; No), the
CPU 401 will stand by. For example, if the user X purchases a product
"game 2" at 21:00 on April 29, the CPU 401 registers a user ID "X", a
product group "Game", a purchased product "game 2" and a purchase date
and time "21:00 on April 29" to the history table 101a. Meanwhile, if the
user X purchases "food 1", the CPU 401 will stand by.

[0120] When the purchase history is stored in the history storage unit 101
(Step S102), next, the estimation unit 103 starts a usage-end date and
time estimation processing (Step S103 in FIG. 10).

[0121] First, the estimation unit 103 extracts, from histories recorded in
the history table 101a, histories of a product group to which a product
most recently purchased by the recommendation-receiving user belongs, and
sorts the extracted histories in order of purchase date and time (Step
S201). That is, the estimation unit 103 extracts, from histories recorded
in the history table 101a in FIG. 5, the histories of the product group
"Game", and sorts the extracted histories in order of purchase date and
time, as illustrated in the recommendation-receiving user history table
103a in FIG. 7.

[0122] Next, the estimation unit 103 determines an average usage time A[i]
(i=1 to n) of purchased products (Step S202). For example, the estimation
unit 103 refers to the average usage time table 102a in FIG. 6 and
determines an average usage time of each of purchased products "game 3",
"game 1", "game 5", "game 4" and "game 2" in FIG. 7 to be "60 hours", "20
hours", "30 hours", "40 hours" and "50 hours", respectively.

[0124] Next, the estimation unit 103 determines a usage time ratio
c[i]=(T[i+1]-T[i])/A[i] (i=1 to n-1) for a product P[i] (i=1 to n-1)
registered in the recommendation-receiving user history table 103a (Step
S204). For example, the estimation unit 103 determines, based on values
determined in Step S202 and S203, a usage time ratio of purchased
products "game 3", "game 1", "game 5" and "game 4" to be "3.60", "4.85",
"4.80" and "1.75", respectively.

[0125] Next, the determined usage time ratio c[i] (i=1 to n-1) are
substituted into the above Expression 1 thereby to determine a usage time
ratio c[n] of the most recently purchased product P[n] (Step S205). For
example, assuming that w=0.95, the estimation unit 103 substitutes a
usage time ratio c[i] (i=1 to 4) of a purchased product that was
determined in Step S204 into Expression 1 to determine c[5]=3.71.

[0126] The estimation unit 103 substitutes the determined A[n] and c[n]
into the above Expression 2 to determine a usage-end date and time T[n+1]
of P[n] (Step S206). For example, the estimation unit 103 substitutes an
average usage time A[5] determined in Step S202 and a usage time ratio
c[5] determined in Step S205 into Expression 2 to determine a usage-end
date and time T[6] of "game 2" in FIG. 4 to be "14:30 on May 7".

[0127] The order of the flow chart in FIG. 10 is one example, and the
order is not limited to this. For example, processing to determine an
average usage time A[i] (i=1 to n) may be performed at any point between
Step S201 and Step S205.

[0128] When a usage-end date and time T[n+1] of P[n] is determined by the
usage-end date and time estimation processing (Step S103 in FIG. 10), the
presentation unit 104 determines whether the current time reaches the
estimated usage-end date and time (Step S104). If the presentation unit
104 determines that the current time has reached the estimated usage-end
date and time (Step S104; Yes), the presentation unit 104 presents a
product recommendation message recommending the predetermined product to
the user (Step S105). For example, the presentation unit 104 sends, for
example, the image 500 as illustrated in FIG. 8 to an e-mail address of
the user X. Meanwhile, if the current time has not reached the estimated
usage-end date and time (Step S104; No), the presentation unit 104 will
stand by until the current time reaches the estimated usage-end date and
time. After the presentation unit 104 presents the product recommendation
message, processing returns to Step S101 and processing is repeated until
a manager and/or the like of the product recommendation device 100
instructs the processing to stop.

[0129] According to the present embodiment, for a type of product for
which an amount of time required to finish usage varies according to each
purchased product, a date and time when a user finishes using a product
is estimated, and when the estimated date and time is reached, a product
is recommended, thereby enabling a product to be recommended to the user
at a suitable timing.

EMBODIMENT 2

[0130] A product recommendation device 100 according to Embodiment 2
estimates a date and time when a user finishes using a product on the
basis of information on an amount of time assumed to be required by an
average user to use a product, information on an interval between
purchases of products, and a season in which a product is purchased, and
recommends the predetermined product when the estimated date and time is
reached.

[0131] The product recommendation device 100 according to Embodiment 2 is
composed of the history storage unit 101, the time storage unit 102, the
estimation unit 103 and the presentation unit 104, as illustrated in FIG.
2. The history storage unit 101, time storage unit 102 and presentation
unit 104 according to the present embodiment have the same functions as
those of Embodiment 1. The estimation unit 103 that has a function
different from that of Embodiment 1 will be described.

[0132] Hereinafter, a season includes not only a category of "spring",
"summer", "autumn" and "winter" but also a predetermined period such as
"year-end through New Year", "summer holidays" and/or the like.

[0133] The estimation unit 103 acquires, from history information stored
in the history storage unit 101, history information associated with a
user identifier of a recommendation-receiving user, determines, from the
acquired history information, a usage time required from start of usage
by the recommendation-receiving user of a product other than a product
most recently purchased by the recommendation-receiving user until end of
usage thereof, and estimates a usage-end date and time of the product
most recently purchased by the recommendation-receiving user on the basis
of the determined usage time, an assumed time on the product associated
with the acquired history information, the assumed time being stored in
the time storage unit 102, and a seasonal coefficient. A seasonal
coefficient Q is a coefficient to multiply a usage time ratio c[n] by in
the above Expression 2 and a value defined by a purchase date and time
T[n]. It is estimated that the smaller the seasonal coefficient becomes,
the earlier a usage-end date and time T[n+1] comes.

[0134] Accordingly, the CPU 401 functions as the estimation unit 103.

[0135] It is generally considered that the user has more time to use games
and books on holidays than on non-holidays. That is, it is considered
that a usage time for a user to use a product varies according to a
calendar. Holidays of a user vary according to the user's attribute. For
example, if the user is an office worker, the user's holidays are usually
year-end through New Year and national holidays. If the user is a
student, the user has summer holidays, spring holidays and/or the like in
addition to these holidays. A seasonal coefficient is for reflecting such
a variation of a usage time according to a calendar in determining the
user's usage time T[i+1]-T[i] (i=1 to n-1).

[0136] With respect to a seasonal coefficient, a table to associate a user
ID 601a1, an attribute 601a2, a period 601a3 and a seasonal coefficient
601a4 with one another and register them (hereinafter referred to as
"seasonal coefficient table 601a") is preliminarily provided. FIG. 11
illustrates an example of the seasonal coefficient table 601a. If the
user X is a student, a usage time is considered to change (increase)
during a period of national holidays (April 29 through May 5), summer
holidays (July 25 through August 31), winter holidays (December 25
through January 7) and/or the like, compared with other periods.
Accordingly, a seasonal coefficient less than or equal to one is
associated with these periods and registered. If the user Y is an office
worker, a usage time is considered to change (increase) during national
holidays (April 29 through May 5) and year-end through New Year holidays
(December 30 to January 3). Accordingly, a seasonal coefficient of less
than or equal to one is associated with these periods and registered.

[0137] The estimation unit 103 according to the present embodiment
determines a usage-end date and time T[n+1] of the product P[n] most
recently purchased by the recommendation-receiving user as follows:

T[n+1]=T[n]+A[n]Qc[n] Expression 3

where a seasonal coefficient Q is determined from a purchase date and
time T[n] of a product P[n] by referring to the seasonal coefficient
table 601a. For example, since a purchase date and time T[5] of a product
"game 2" is "21:00 on April 29" as illustrated in the example in FIG. 7,
the seasonal coefficient Q is determined to be "0.6". In the case where a
usage time ratio c[5]=3.71 has been determined, it follows that
A[5]Qc[5]=111.3 hours, and the estimation unit 103 determines a usage-end
date and time T[6] of "game 2" (P[5]) to be "12:18 on May 4".

[0138] Hereinafter, operation performed by each unit of the product
recommendation device 100 according to the present embodiment will be
described. The product recommendation device 100 according to the present
embodiment performs processing different from that of Embodiment 1 in a
usage-end date and time estimation processing and performs the same
processing as illustrated in the flow chart in FIG. 9 in processing other
than the usage-end date and time estimation processing. Hereinafter, the
usage-end date and time estimation processing in which a different
processing is performed will be described with reference to a flow chart
in FIG. 12. Since Step S301 to Step S305 in the flow chart of FIG. 12 are
the same as Step S201 to Step S205 in the flow chart of FIG. 10, the
explanation of these steps will be left out.

[0139] In Step S305 a usage time ratio c[n] is determined, and then the
estimation unit 103 determines a seasonal coefficient Q (Step S306). For
example, if a purchase date and time T[5] of a most recently purchased
product "game 2" is "21:00 on April 29" as illustrated in the example in
FIG. 7, the estimation unit 103 refers to the seasonal coefficient table
601a in FIG. 11 to determine the seasonal coefficient Q to be "0.6".

[0140] The estimation unit 103 substitutes an average usage time A[n]
determined in Step S302, a usage time ratio c[n] of a product P[n]
determined in Step S305, and the seasonal coefficient Q determined in
Step S306 into the above Expression 3 to determine a usage-end date and
time T[n+1] of the product P[n] (Step S307). For example, assuming that
A[5]=50 and c[5]=3.71, a usage-end date and time T[6] of a product "game
2" (P[5]) is determined to be 12:18 on May 4.

[0141] Processing to determine the seasonal coefficient Q may be performed
at any timing before Step S307.

[0142] According to the present embodiment, taking a variation of the
user's usage time according to a calendar into consideration, a date and
time when the user finishes using a purchased product can be estimated
and therefore purchase of a product can be encouraged to the user at a
suitable timing.

EMBODIMENT 3

[0143] A product recommendation device 100 according to Embodiment 3 uses
information on an amount of time that is assumed to be required by an
average user to use a product, as well as information on an interval
between purchase and sales of a product or an interval between purchases
of products to estimate a date and time when a user finishes using a
product, and recommend the predetermined product when the estimated date
and time is reached.

[0144] The product recommendation device 100 according to Embodiment 3 is
composed of the history storage unit 101, the time storage unit 102, the
estimation unit 103 and the presentation unit 104, as illustrated in FIG.
2. The time storage unit 102 and presentation unit 104 according to the
present embodiment have the same functions as those of Embodiment 1.
Hereinafter, the history storage unit 101 and estimation unit 103 that
have different functions from those of Embodiment 1 will be described.

[0145] Hereinafter, using, as an example, a case where the user X performs
a purchase and sales activity as illustrated in FIG. 13, function of each
unit will be described.

[0146] The history storage unit 101 stores history information, the
history information including a user identifier of each user who
purchased any of products included in a predetermined product group, the
purchased product, a purchase date and time of the product, and a sales
date and time when the purchased product was sold. The predetermined
product group is the same as that of Embodiment 1.

[0147] Accordingly, the RAM 403 or the external memory 409 function as the
history storage unit 101.

[0148] Specifically, the history storage unit 101 stores a table (history
table 101a) to which a user ID 101a1 of a user who purchased a product, a
product group 101a2 to which the product purchased by the user belongs,
the purchased product 101a3 (p[i] (i=1 to N)), a purchase date and time
101a4 (t[j] (j=1 to M, M: an arbitrary number)) and a sales date and time
101a5 (t[j] (j=1 to M)) are associated with one another and registered.
The purchase and sales history registered in the history table 101a is on
a product that belongs to the predetermined product group, and a purchase
and sales history of a product that belongs to a product group other than
the predetermined product group is not registered.

[0149]FIG. 14 illustrates an example of the history table 101a in the
case where the user X performs the purchase and sales activity in FIG.
13.

[0150] The user X purchased 15 products p[i] (i=1 to 15), and eight of
them belong to products in the predetermined product group ("Game",
"Book" and "DVD"). Two products ("game 5" and "game 1") of the products
in the predetermined product group were sold. For example, since the user
"X" purchased the product "game 1" at "22:00 on April 16" and sold the
product "game 1" at "22:00 on April 24", an user ID "X", "Game" that is a
product group of game 1, the product "game 1", a purchase date and time
"22:00 on April 16" and a sales date and time "22:00 on April 24" are
associated with one another and registered to in the history table 101a.

[0151] Hereinafter, similarly, a purchase history of a product that
belongs to the predetermined product group is registered in the history
table 101a. In the history table 101a, purchase histories of a plurality
of users other than the user X are also registered in the same fashion.

[0152] The estimation unit 103 acquires, from history information stored
in the history storage unit 101, history information associated with a
user identifier of the recommendation-receiving user, determines, from
the acquired history information, a usage time required from start of
usage by the recommendation-receiving user of a product other than a
product most recently purchased by the recommendation-receiving user
until end of usage thereof, and estimates a usage-end date and time of
the product most recently purchased by the recommendation-receiving user
on the basis of the determined usage time and an assumed time on a
product associated with the acquired history information, the assumed
time being stored in the time storage unit 102.

[0153] Accordingly, the CPU 401 functions as the estimation unit 103.

[0154] Hereinafter, a method will be described in which the estimation
unit 103 estimates a usage-end date and time of a product P[n] most
recently purchased by the recommendation-receiving user.

[0155] First, the estimation unit 103 extracts, from histories registered
in the history table 101a, the histories of the product group to which
the product most recently purchased by the recommendation-receiving user
belongs, sorts the extracted histories in order of purchase date and
time, and temporarily stores the sorted histories in the RAM 403.
Hereinafter, a sorted table will be referred to as
"recommendation-receiving user history table 103a". In the
recommendation-receiving user history table 103a, a user ID 103a1 of the
recommendation-receiving user, a product group 103a2 to which a product
purchased by the user belongs, the purchased product 103a3 (P[i] (i=1 to
n)), a purchase date and time 103a4 (T[i] (i=1 to n)), an average usage
time 103a5 (A[i] (i=1 to n)) determined by referring to the average usage
time table 102a, a sales date and time 103a6 (S[i] (i=1 to n)) when the
purchased product was sold are associated with one another and
registered.

[0156]FIG. 15 illustrates an example of the recommendation-receiving user
history table 103a.

[0157] For example, referring to a recommendation-receiving user as a user
X, a usage-end date and time of a purchased product "game 2" is
determined based on the history table 101a in FIG. 14. In this case, the
estimation unit 103 extracts, from the history table 101a in FIG. 14,
histories that are associated with the user X and a product group "Game",
and sorts the extracted histories in order of purchase date and time as
illustrated in the recommendation-receiving user history table 103a of
FIG. 15. Next, referring to the average usage time table 102a in FIG. 6,
the estimation unit 103 determines an average usage time A[1] (60 hours)
of a purchased product P[1] (game 3), an average usage time A[2] (20
hours) of P[2] (game 1), an average usage time A[3] (30 hours) of P[3]
(game 5), an average usage time A[4] (40 hours) of P[4] (game 4) and an
average usage time A[5] (50 hours) of P[5] (game 2) that all belong to
the product group "Game".

[0158] Next, the estimation unit 103 determines an interval S[i]-T[i] (i=1
to n-1) between purchase and sales of a product P[i] (i=1 to n-1). Sales
of a product P[i] after purchase thereof can be considered that usage of
the product P[i] has been finished. For example, sales of a product "game
3" by the user X after purchase thereof can be interpreted as that the
user X has beaten "game 3" or becomes bored with "game 3". Accordingly,
in the present embodiment, a sales date and time S[i] is deemed to be a
date and time when usage of a product P[i] has been finished, and an
interval S[i]-T[i] between purchase and sales is deemed to be an amount
of time (usage time) required by the user to finish using a product P[i].
If there is no sales history of a product P[i] (i=1 to n-1), an interval
between purchases T[i+1]-T[i] (i=1 to n-1) is deemed to be a usage time,
as illustrated in Embodiment 1.

[0159] The estimation unit 103 determines a usage time ratio
c[i]=(S[i]-T[i])/A[i] or c[i]=(T[i+1]-T[i])/A[i] of a product P[i] (i=1
to n-1) of the user.

[0160] In the example of FIG. 15, the estimation unit 103 determines a
usage time T[2]-T[1] (=216 hours) of a product P[1], a usage time
S[2]-T[2] (=192 hours) of a product P[2], a usage time S[3]-T[3] (=49
hours) of a product P[3] and a usage time T[5]-T[4] (=70 hours) of a
product P[4], and determines a usage time ratio c[1] (=3.60) of the
product P[1], a usage time ratio c[2] (=9.60) of the product P[2], a
usage time ratio c[3] (=1.63) of the product P[3], and a usage time ratio
c[4] (=1.75) of the product P[4].

[0161] Next, the estimation unit 103 determines a usage time ratio c[n]
between an amount of time (S[n]-T[n] or T[n+1]-T[n]) estimated to be
required to finish using a currently purchased product P[n], and an
average usage time A[n]. Since a sales date and time S[n] of the product
P[n] or a purchase date and time T[n+1] of a new product P[n+1] (a
usage-end date and time of the product P[n]) is not a measured value,
c[n] is estimated based on the determined c[i] (i=1 to n-1). c[n] can be
determined by substituting c[i] (i=1 to n-1) into the above Expression 1.

[0162] For example, in the example (n=5) of FIG. 15, assuming that w=0.95,
it determines that c[5]=4.06.

[0163] By using the determined c[n], a usage-end date and time T[n+1]
(=S[n]) of the product P[n] is determined from the above Expression 2.

[0164] For example, in the example of FIG. 15, since A[5]c[5]=203 hours, a
usage-end date and time T[6] of a product P[5] (game 2) is determined to
be "8:00 on May 8".

[0165] Next, operation performed by each unit of the product
recommendation device 100 will be described with reference to flow charts
in FIGS. 16 and 17. When the product recommendation device 100 is turned
on, the CPU 401 starts a product recommendation processing illustrated in
a flow chart of FIG. 16. Referring to a recommendation-receiving user as
a user X, a case where the user X performs the purchase and sales
activity illustrated in FIGS. 13 and 14 will be described as an example.

[0166] The CPU 401 determines whether a product in the predetermined
product group was purchased (Step S401). If the CPU 401 determines that
the product was purchased (Step S401; Yes), the CPU 401 registers a user
ID of a user who purchased the product, a product group to which the
purchased product belongs, the purchased product p[N] and a purchase date
and time t[M] in the history table 101a (Step S402). Meanwhile, if the
CPU 401 does not determine that the product in the predetermined product
group was purchased (Step S401; No), the CPU 401 determines whether any
of purchased products p[i] (i=1 to N) stored in the history storage unit
101 was sold (Step S403). For example, if a product group and product
name of the purchased product p[i] correspond to or is similar to a
product group and product name of a sold product, it is determined that
the purchased product p[i] stored in the history storage unit 101 was
sold. If the CPU 401 determines that any of the purchased products p[i]
(i=1 to N) was sold (Step S403; Yes), the CPU 401 associates a sales date
and time t[j] (j=1 to M) with a user ID of a user who purchased the
product, a product group to which the purchased product belongs, the
purchased product p[i] (i=1 to N) and a purchase date and time t[i] (i=1
to M) and registers the sales date and time t[j] (j=1 to M) in the
history table 101a (Step S404). Then, the CPU 401 presents a product
recommendation message recommending a product that belongs to the same
product group as that of the sold product (Step S407). Meanwhile, if the
CPU 401 does not determine that any of the purchased product p[i] (i=1 to
N) was sold (Step S403; No), the processing returns to Step S401.

[0167] For example, as illustrated in FIGS. 13 and 14, if the user X
purchases a product "game 2" at 21:00 on April 29, the CPU 401 registers
a user ID "X", a product group "Game", a purchased product "game 2" and a
purchase date and time "21:00 on April 29" in the history table 101a. If
the user X sells a product "game 5" of a product group "Game" at 0:00 on
April 23, the CPU 401 determines whether the product "game 5" in a
product group "Game" as a purchased product is registered in the history
table 101a. Since the product "game 5" of a product group "Game" is
registered in the history table in FIG. 14, the CPU 401 associates the
sales date and time "0:00 on April 23" with a user ID "X", a product
group "Game", a purchased product "game 5" and a purchase date and time
"23:00 on April 20" and registers the sales date and time "0:00 on April
23" in the history table 101a. Then the presentation unit 104 presents a
product recommendation message recommending any of products that belong
to the product group "Game" to the user X. Meanwhile, if the user X
purchases food 1, the CPU 401 causes the processing to return to Step
S401 and will stand by.

[0168] When the purchase history is stored in the history storage unit 101
(Step S402), the estimation unit 103 starts a usage-end date and time
estimation processing (Step S405 in FIG. 17).

[0169] First, the estimation unit 103 extracts, from histories recorded in
the history table 101a, the history information on product group to which
a product most recently purchased by the recommendation-receiving user
belongs and sorts the extracted history information in order of purchase
date and time (Step S501). That is, the estimation unit 103 extracts,
from histories registered in the history table 101a of FIG. 14, histories
of a product group "Game" and sorts the extracted histories in order of
purchase date and time, as illustrated in the recommendation-receiving
user history table 103a of FIG. 15.

[0170] Next, the estimation unit 103 obtains an average usage time A[i]
(i=1 to n) of a purchased product, by referring to the average usage time
table 102a (Step S502). For example, the estimation unit 103 refers to
the average usage time table 102a in FIG. 6 to obtain an average usage
time of each of purchased products "game 3", "game 1", "game 5", "game 4"
and "game 2" included in FIG. 15 to be "60 hours", "20 hours", "30
hours", "40 hours" and "50 hours", respectively.

[0171] Next, the estimation unit 103 determines whether there is a sales
history with respect to purchased products P[i] (i=1 to n-1) registered
in the recommendation-receiving user history table 103a (Step S503). If
the estimation unit 103 determines that there is the sales history (Step
S503; Yes), a usage time of the purchased product P[i] (i=1 to n-1) is
determined by S[i]-T[i] (i=1 to n-1) (Step S504). Meanwhile, if the
estimation unit 103 determines that there is no sales history (Step S503;
No), the usage time of the purchased product P[i] (i=1 to n-1) is
determined by T[i+1]-T[i] (i=1 to n-1) (Step S505). For example, the
estimation unit 103 determines a usage time S[i]-T[i] (i=2, 3) of each of
the purchased products "game 1" and "game 5" included in FIG. 15 to be
"192 hours" and "49 hours", respectively and determines a usage time
T[i+1]-T[i] (i=1, 4) of each of the "game 3" and "game 4" included in
FIG. 15 to be "216 hours" and "70 hours", respectively.

[0172] Next, the estimation unit 103 determines a usage time ratio
c[i]=(S[i]-T[i])/A[i] (i=1 to n-1) or c[i]=(T[i+1]-T[i])/A[i] (i=1 to
n-1) of the product P[i] (i=1 to n-1) registered in the
recommendation-receiving user history table 103a (Step S506). For
example, the estimation unit 103 determines, from the values determined
in Step S502, Step S504 and Step S505, usage time ratios of the purchased
product "game 3", "game 1", "game 5" and "game 4" to be "3.60", "9.60",
"1.63" and "1.75", respectively.

[0173] Next, the determined usage time ratio c[i] (i=1 to n-1) is
substituted into the above Expression 1 to determine a usage time ratio
c[n] of a most recently purchased product P[n] (Step S507). For example,
assuming that w=0.95, the estimation unit 103 substitutes a usage time
ratio c[i] (i=1 to 4) of the purchased product determined in Step S506
into Expression 1 to determine c[5]=4.06.

[0174] The estimation unit 103 substitutes the determined A[n] and c[n]
into the above Expression 2 to determine a usage-end date and time T[n+1]
(=S[n]) of P[n] (Step S508). For example, the estimation unit 103
substitutes the average usage time A[5] determined in Step S502 and the
usage time ratio c[5] determined in Step S507 into Expression 2 to
determine a usage-end date and time T[6] of "game 2" in FIG. 13 to be
"8:00 on May 8".

[0175] The order of the flow chart in FIG. 17 is one example and the order
is not limited to this order. For example, processing to determine an
average usage time A[i] (i=1 to n) may be performed at any timing between
Step S501 and Step S508.

[0176] When the usage-end date and time T[n+1] of P[n] is determined by
the usage-end date and time estimation processing (Step S405 in FIG. 17),
the presentation unit 104 determines whether a current time reaches the
estimated usage-end date and time (Step S406). If the presentation unit
104 determines that the current time has reached the estimated usage-end
date and time (Step S406; Yes), the presentation unit 104 presents a
product recommendation message recommending the predetermined product to
the user (Step S407). For example, the image 500 as illustrated in FIG. 8
is sent to an e-mail address of the user X. Meanwhile, if the current
time has not reached the usage-end date and time (Step S406; No), the
presentation unit 104 will stand by until the current time reaches the
estimated usage-end date and time.

[0177] In the present embodiment, in determining a usage time of a user,
if there is a sales history in the recommendation-receiving user history
table 103a, a sales date and time is preferentially used, but a way to
determine the usage time is not limited to this. For example, the
estimation unit 103 may compare a sales date and time S[i] and a purchase
date and time T[i+1], and use an earlier date and time as a usage-end
date and time of a product P[i] to determine a usage time. In the example
of FIG. 15, a sales date and time S[2] of a product "game 1" is later
than a purchase date and time T[3] of the subsequent product "game 5".
Accordingly, a usage-end date and time of the product "game 1" is used as
a purchase date and time T[3] thereby to determine a usage time of a
product "game 2" to be T[3]-T[2] (=97 hours). Meanwhile, a sales date and
time S[3] of the product "game 5" is earlier than a purchase date and
time T[4] of the subsequent product "game 4". Accordingly, a usage-end
date and time of the product "game 5" is used as a sales date and time
S[3] thereby to determine a usage time of the product "game 5" to be
S[3]-T[3] (=49 hours).

[0178] According to the present embodiment, by using a date and time when
a user sold a purchased product, a date and time when the user finished
using the product is accurately estimated, thereby recommending a product
to the user at a suitable timing.

EMBODIMENT 4

[0179] A product recommendation device 100 according to Embodiment 4
adjusts information on an amount of time assumed to be required by an
average user to use a product on the basis of a purchase and sales
history of a recommendation-receiving user, uses the adjusted information
on an amount of time and information on an interval between purchase and
sales of a product or an interval between purchases of products to
estimate a date and time when the user finishes using a product, and
recommends the predetermined product when the estimated date and time is
reached.

[0180] The product recommendation device 100 according to Embodiment 4 is
composed of the history storage unit 101, the time storage unit 102, the
estimation unit 103 and the presentation unit 104, as illustrated in FIG.
2. The history storage unit 101, estimation unit 103 and presentation
unit 104 in the present embodiment have the same functions as those of
Embodiment 3. Hereinafter, the time storage unit 102 having a different
function will be described.

[0181] The time storage unit 102 stores, for each of products included in
a predetermined product group, an assumed time that is assumed to be
required from start of usage of the product until end of usage thereof.
Among history information, history information including a purchase date
and time and a sales date and time is used to determine an interval
between the purchase date and time and the sales date and time of a
product associated with the history information, and the assumed time on
the product stored in the time storage unit 102 is adjusted on the basis
of the determined interval.

[0182] In the recommendation-receiving user history table 101a of FIG. 15,
a way to adjust an average usage time A[i] (i=1 to n) in FIG. 6 will be
described by using "game 5" of which a purchase date and time and a sales
date and time are registered, from history information of a
recommendation-receiving user "X", as an example.

[0183] For example, an adjusted average usage time A[i] (i=1 to n) is
determined as follows:

αA[i]+(1-α)(S[i]-T[i]) Expression 4

where α is an arbitrary number that is greater or equal to zero and
less or equal to one. The smaller a value of α becomes, the more
the adjusted average usage time is indicated by an interval between
purchase and sales of a recommendation-receiving user with respect to a
preliminarily-registered average usage time. Hereinafter, let α to
be 0.95.

[0184] An interval S[3]-T[3] between a purchase date and time and a sales
date and time of game 5 (P[3]) is 49 hours. An average usage time A[3] of
game 5 is 30 hours. Accordingly, an adjusted average usage time A[3] is
determined to be 30.95 hours from Expression 4.

[0185] In addition or alternatively, an assumed time of a first product
stored in the time storage unit 102 is adjusted based on an interval
between a purchase date and time included in history information of the
first product and a purchase date and time included in history
information on a second product, the second product being most recently
purchased among products purchased by the same user of the first product
after purchase of the first product.

[0186] For example, an adjusted average usage time A[i] (i=1 to n) is
determined as follows:

βA[i]+(1-β)(T[i+1]-T[i]) Expression 5

where β is an arbitrary constant number that is greater or equal to
zero and less or equal to one. The smaller a value α becomes, the
more the adjusted average usage time is indicated by an interval between
purchases of a recommendation-receiving user with respect to a
preliminarily-registered average usage time. Hereinafter, let β to
be 0.95.

[0187] An interval T[2]-T[1] between a purchase date and time T[1] of game
3 (P[1]) and a purchase date and time T[2] of the subsequent game 1
(P[2]) is 216 hours, and an average usage time A[1] of game 3 is 60
hours. Accordingly, an adjusted average usage time A[1] is determined to
be 67.8 hours from Expression 5.

[0188] Hereinafter, assuming that the estimation unit 103 adjusts an
average usage time in estimating a usage-end date and time; if there is
history information of a sales date and time of a
recommendation-receiving user, the average usage time is adjusted based
on Expression 4; and if there is no history information of a sales date
and time, the average usage time is adjusted based on Expression 5.

[0189] Next, operation performed by each unit of the product
recommendation device 100 according to the present embodiment will be
described. The product recommendation device 100 according to the present
embodiment performs a processing different from that of Embodiment 3 in a
usage-end date and time estimation processing, and performs the same
processing as illustrated in the flow chart of FIG. 16 in a processing
other than the usage-end date and time estimation processing.
Hereinafter, a usage-end date and time estimation processing to perform a
different processing will be described with reference to a flow chart in
FIG. 18. Referring to a recommendation-receiving user as a user X, a case
where the user X performs the purchase and sales activity as illustrated
in FIGS. 13 and 14 will be described as an example. Since Steps S601,
S604 and S606 to S609 in the flow chart of FIG. 18 are the same as Steps
S501, S504 and S505 to S508 of the flow chart in FIG. 17, the description
will be left out.

[0190] After history information is sorted in order of purchase date and
time in Step S601, the estimation unit 103 determines whether there is a
sales history for a purchased product P[i] (i=1 to n-1) registered in the
recommendation-receiving user history table 103a (Step S602). If the
estimation unit 103 determines that there is the sales history (Step
S602; Yes), the estimation unit 103 determines an interval between a
purchase date and time and a sales date and time of the purchased product
P[i] (i=1 to n-1), and adjusts an average usage time in the average usage
time table 102a of FIG. 6 on the basis of the determined interval (Step
S603). Then, the estimation unit 103 performs processing Step S604
onwards to estimate a usage-end date and time. Meanwhile, if the
estimation unit 103 determines there is no sales history (Step S602; No),
the estimation unit 103 determines an interval between a purchase date
and time of the purchased product P[i] (i=1 to n-1) and a purchase date
and time of the subsequent purchased product P[i+1], and adjusts an
average usage time in the average usage time table 102a of FIG. 6 on the
basis of the determined interval. Then, the estimation unit 103 performs
processing Step S606 onwards to estimate a usage-end date and time.

[0191] For example, if the purchased product is "game 5", the estimation
unit 103 determines that there is a sales history and adjusts an average
usage time "30 hours" in the average usage time table 102a of FIGS. 6 to
"30.95 hours" on the basis of Expression 4. For example, if the purchased
product is "game 3", the estimation unit 103 determines that there is no
sales history, and adjusts an average usage time "60 hours" in the
average usage time table 102a of FIGS. 6 to "67.8 hours" on the basis of
Expression 5.

[0192] The estimation unit 103 may estimate a usage-end date and time by
using an adjusted average usage time for a product of which a purchase
date and time and a sales date and time are registered as history
information and by using a non-adjusted average usage time for a product
of which a sales history is not registered.

[0193] A way to adjust an assumed time (average usage time) stored in the
time storage unit 102 is not limited to the above way. For example, if an
interval between purchases and an interval between purchase and sales by
a recommendation-receiving user tends to be longer than an interval
between purchases or an interval between purchase and sales by other
users, an average usage time registered in the average usage time table
102a may be lengthened by multiplying by a coefficient greater than one.

[0194] According to the present embodiment, in determining an average
usage time, by reflecting a purchase activity of a
recommendation-receiving user, a date and time when the user finished
using a product can be accurately estimated and a product can be
recommended to the user at a suitable timing.

[0195] The present invention is based on Japanese Patent Application No.
2010-077359 filed on March 30, 2010. The specification, claims and
drawings of Japanese Patent Application No. 2010-077359 shall be
incorporated into the specification of the present application by
reference.

[0196] In the present invention, various embodiments and modifications
thereof can be performed without departing from an extensive principles
and scope of the present invention. The aforementioned embodiments are
intended to explain the present invention, not to limit the scope of the
present invention. That is, the scope of the present invention is defined
by claims, not by embodiments. Various modifications performed within the
scope of claims and the inventions equivalent to the claims are deemed to
be within the scope of the present invention.

INDUSTRIAL APPLICABILITY

[0197] The present invention can provide a product recommendation device,
a product recommendation method, a program and a recording medium that
are suitable for estimating a date and time when a user finishes using a
product and recommending a product to the user at a suitable timing, for
a type of products of which time required to finish usage varies
according to each purchased product.